good evening, i'm dan ashley. >> the group is trying to get the federal court to overturn the ban on public nudity, scheduled to take affect next month. the city wants the case tossed. abc news joins us live from the federal court house with the story. carolyn? >> well, it began with supervisor scott weiner who says his constituents complained two years about a group of naked guys hanging out in the castro neighborhood. he convinced colleagues on the board to enact this ban, taking affect february 1 unless today's legal challenge is successful. anyone who visits the federal building knows it's almost always cold and windy. this time, they're stripping down to protest the stripping away of what they consider a civil liberty. this is like asking a gay person 20, 30 years ago. why is it important to you to be gay? >> george davis is a plaintiff in this lawsuit, asking a judge to step n last month, san francisco supervisors passed a measure prohibiting most displays of public nudity. the attorney says it's a violation of free speech. >> my client has been for some time, before this ordin